But even if you maintain
a clean tank, some factors may have determined your boat’s tank life
long before you made that first payment. For instance, installation. The
tank should not lie directly on the boat’s bottom. If it does, "moisture
will get trapped under the tank and cause corrosion," says Appelt.
Joey Weller, customer relations manager for Grady-White Boats, concurs,
adding that his company sets its aluminum tanks on vinyl protectors mounted
to the subfloor, which allows air to circulate around the tank, minimizing
moisture. Appelt recommends that tanks sit on metal rails secured to the
boat’s substrate. That way the rails will corrode first, giving you
fair warning.

Many fuel tanks today
are even epoxy-coated outside to help combat the effects the saltwater
environment. This may be worth doing in the off season if your boat’s
tanks are in good shape. Several fuel tank manufacturers I contacted said
they make their own epoxy-based coatings for tanks, but they weren’t
eager to reveal the special ingredients. However, there is an over-the-counter
product called Gluvit, which is an epoxy-based waterproof sealer that
can be painted on and works on aluminum. It comes in quarts and gallons
and retails for around $24.99 and $64.99, respectively. Keep in mind this
is not a cure-all. The expansion and contraction of the tank will differ
from that of the sealer, and eventually the sealer will wear or crack.
You can also try coating the tank with WEST SYSTEM® epoxy and fiberglass
cloth. But consult a professional before taking on this project.

In the end, you need
to employ multiple strategies in the battle to keep the saltwater environment
from damaging your boat’s fuel tanks. Fuel conditioners can reduce
water and algae levels inside, and keeping your tanks’ exteriors
clean, well ventilated, and off the bottom of your boat will help maintain
their external integrity. Specifying tanks of monel when you’re building
or refitting will ensure a longer life than aluminum but, of course, at
a price. Appelt says monel tanks can cost as much as 10 times the price
of similar-size aluminum tanks. Well-built fiberglass tanks can also be
durable. I’ve seen boats with integral fiberglass tanks more than
two decades old that are still in good shape.

No matter what material
your boat’s tanks are made of, preventive measures like those mentioned
here are necessary to keep them clean and corrosive-free for seasons to
come. After all, you don’t want to miss two weeks of boating while
someone repairs or replaces your fuel tanks.